Wearable Conductive CuCD@FCH nanoprobe for Dual Detection of Biomarker in Sweat and Human Motion Detection

Abstract

Hydrothermally synthesized copper-doped carbon dot (CuCDs) were used for fluorescence and electrochemical detection of biomarkers like calcium and glycine. The fluorescence intensity of CuCD is diminished after the addition of Ca2+ biomarkers due to the quenching process. Ca@CuCD nanoconjugate serve as an excellent platform for the recognition of glycine. The feeble emission of Ca@CuCD increases substantially in the presence of glycine due to aggregation-induced emission. At the same time, there was a 5-fold increase in the current response of the Ca@Cu-CD modified electrode as compared to the control. For real-life detection of biomarker Ca2+ ion in human sweat, a fluorescent conductive hydrogel (FCH) has been fabricated by crosslinking PVA and agar in presence of CuCD. The developed FCH synergistically addresses “four birds-in-one-stone”, i.e. Ca 2+recognition, ionic conductance (4.2 Sm-1 ), fluorescence, and stretchability (160%). The hydrogel patch sensor can monitor Ca2+ levels in sweat in both fluorescence and electrical mode. At the same time because of excellent skin adhesiveness and flexibility FCH sensor can be attached to any joint to monitor strain induced by body motion in both electrical and fluorescence modes.